Behaviors of Spherical and Nonspherical Particles in a Square Pipe Flow

Abstract

The lattice Boltzmann method (LBM) for multicomponent immiscible fluids is applied to the simulations of solid-fluid mixture flows including spherical or non-spherical particles in a square pipe at Reynolds numbers of about 100. A spherical solid particle is modeled by a droplet with strong interfacial tension and large viscosity, and consequently there is no need to track the moving solid-liquid boundary explicitly. Nonspherical (discoid, flat discoid, and biconcave discoid) solid particles are made by applying artificial forces to the spherical droplet. It is found that the spherical particle moves straightly along a stable position between the wall and the center of the pipe (the Segré-Silberberg effect). On the other hand, the biconcave discoid particle moves along a periodic helical path around the center of the pipe with changing its orientation, and the radius of the helical path and the polar angle of the orientation increase as the hollow of the concave becomes large.

Forcing scheme in pseudopotential lattice Boltzmann model for multiphase flows

“…Ever since, many multiphase LB models have been developed. Generally, these models can be classified into four categories: the color-gradient model [10,11], the pseudo-potential model [8,9,[12][13][14][15][16], the free-energy model [17][18][19][20][21], and the kinetic-theory-based model [22][23][24]. Among these models, the pseudo-potential LB model, which is also called Shan-Chen model, has attracted much attention.…”

Ternary free-energy lattice Boltzmann model with tunable surface tensions and contact angles

“…While a wide range of LB models have been developed for the binary case [24][25][26][27][28][29][30][31][32][33][34][35], systems with three or more * Email: halim.kusumaatmaja@durham.ac.uk fluid components in comparison have received much less attention in the LB community. Several ternary models have been proposed to study water-oil-amphiphile mixtures [36][37][38][39], with two bulk phases, and an amphiphile phase that prefers to locate at the oil-water interface.…”

“…The free energy formalism followed in this work is a top-down approach, where we start by writing the free energy of the fluids [24][25][26][27][28]. The form of the free energy functional should capture the intended features of the thermodynamics of the system, e.g., the miscibility of the components and surface tension between different fluids.…”

Pattern formation in liquid-vapor systems under periodic potential and shear

“…Several approaches have been previously adopted to model nonideal fluids by using the lattice Boltzmann equation (LBE). They can be mainly divided in four groups: Color-gradient models [7,8], pseudopotential models [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], free-energy models [28][29][30][31][32][33][34], and kinetic models [35][36][37][38][39][40][41][42][43][44]. The main difference among the cited models is related to the procedure to introduce intermolecular force into multi-phase LBE.…”